Passenger vehicles may include fuel cell (“FC”) systems to power certain features of a vehicle's electrical and drivetrain systems. For example, a FC system may be utilized in a vehicle to power electric drivetrain components of the vehicle directly (e.g., using electric drive motors and the like) and/or via an intermediate battery system. Hydrogen is one possible fuel that may be used in a FC system. Hydrogen is a clean fuel that can be used to efficiently produce electricity in a FC system. A hydrogen FC system is an electrochemical device that may include an electrolyte between an anode and a cathode. The anode receives hydrogen gas and the cathode receives oxygen or air. The hydrogen gas is dissociated in the anode to generate free hydrogen protons and electrons. The hydrogen protons may be selectively conducted across the electrolyte. The electrons from the anode cannot pass through the electrolyte, and thus are directed through a load to perform work before being sent to the cathode. The hydrogen protons react with the oxygen and the electrons in the cathode to generate water.
Proton exchange membrane fuel cells (“PEMFC”) may be used in FC-powered vehicles. A PEMFC generally includes a solid polymer electrolyte proton conducting membrane, such as a perfluorosulfonic acid membrane. An anode and cathode included in a PEMFC may include finely divided catalytic particles (e.g., platinum particles) supported on carbon particles and mixed with an ionomer. A catalytic mixture may be deposited on opposing sides of the membrane.
Over time, a PEMFC may experience operating voltage loss due to a variety of mechanisms and/or processes, thereby reducing performance of the PEMFC. Some PEMFC voltage loss may be recoverable by initiating voltage recovery procedures in the PEMFC, while others may not be recoverable (e.g., losses attributable to electrode degradation or the like). Certain voltage recovery procedures may, however, cause some minimal unrecoverable degradation to the PEMFC. Accordingly, such procedures should be initiated when voltage loss recovery may be effectively realized. It may be further difficult to differentiate recoverable voltage loss from unrecoverable voltage loss, thereby making it difficult to determine when voltage recovery procedures should be performed. Conventional methods may not provide for sufficiently accurate estimation of voltage over the operation life of a FC system, thereby reducing fuel efficiency over the life of the FC system.